Instrument for inscribing an ellipse



July 21, 1970 K. A. BOWEN I 3 v INSTRUMENT FOR INSCRIBING AN ELLIPSE Filed Jan. 21, 1969 2 Sheets-Sheet 1 v INVENTOR. KERM/T A. BOWEN BY 7 Y ATTORNEY y 1; 1970 K. A. BOWEN 3,521,361

INSTRUMENT FOR INSCRIBING AN ELLIPSE Filed Jan. 21, 1969 2 Sheets-Sheet 2 INVENTOR KERMIT A. BOWEN BY v flflksgflzz? ATTORNEY United States Patent 3,521,361 INSTRUMENT FOR INSCRIBING AN ELLIPSE Kermit A. Bowen, 8022 University Place, La Mesa, Calif. 92041 Filed Jan. 21, 1969, Ser. No. 792,739 Int. Cl. B431 11/04 US. CI. 33-30 9 Claims ABSTRACT OF THE DISCLOSURE An instrument for inscribing ellipses comprising an inverted U-shaped frame, the feet of the legs of which rest on the surface to be inscribed. This main frame includes horizontally disposed bearings and a horizontally disposed guideway arranged above the bearings. A second frame oscillates in the bearings and carries a vertically extending, rotatable shaft. The shaft carries two horizontally adjustable arms, the upper arm being guided by the guideway, and the lower arm carries an inscriber which is spring-pressed downwardly. Both arms are frictionally held in adjusted position.

BACKGROUND OF THE INVENTION Description of the prior art The closest prior art known to applicant are his issued patents, No. 2,899,748 issued Aug. 18, 1959, and No. 3,084,441 issued Apr. 9, 1963, both of which are instruments for inscribing ellipses.

The earlier patent was complicated requiring two separate legs 13, a pivotally connected yoke 15, a shaft supporting frame 17 pivoted to yoke 15 and travel pivots between legs 13 and frame 17.

The later patent also was complicated, requiring an extension arm 84 on the rotatable shaft, a pivoted lever 86 on the arm, a spring 114 between the lever 86 and a manipulating rod for moving a style, carried by the lever, downwardly, and a spring 116 for lifting the lever and style off the surface being inscribed.

While these former instruments could be manipulated to inscribe ellipses, exceptionallyperfect execution was necessary, particularly if the style was in the form of an inking pen.

SUMMARY OF THE INVENTION The instrument comprises an inverted U-shaped main frame, the feet of the legs of which rest on the surface on which the ellipse is to be drawn. A guideway which is parallel to said surface is disposed adjacent the top of the frame. Bearings are carried by the frame for supporting a second frame for oscillatory movement on an axis parallel with the guideway. A vertically extending shaft is journalled in the second frame, the upper end of which carries a horizontally adjustable arm which is guided by the guideway. The lower end of the shaft carries a horizontally adjustable arm, which latter directly carries a style. A spring normally urges the style downwardly onto the said surface. The arms are held frictionally in adjusted position. 2

Other features and the advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the invention is illustrated.

Patented July 21, 1970 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the instrument;

FIG. 2 is a view of the instrument, but on a larger scale, the main frame being shown in section, the section being taken along line 22 of FIG. 1, the actuating shaft with the arms thereon being shown in a position ninety degrees from that shown in FIG. 1, and the upper arm is shown extended farther to the left than that shown in FIG. 1;

FIG. 3 is a fragmentary sectional view of both frames and the turning knob for the shaft and the upper arm, the section being taken along line 33 of FIG. 1, but on a larger scale; and

FIG. 4 is a fragmentary sectional view taken along line 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The instrument 20 includes a main frame 22, generally in inverted -U-shape, having two legs 24 and 26 which are connected at their upper ends by a yoke 28 forming a part of a circle. The feet of the legs are in the form of pins 30 which extend into the surface of the paper on which the ellipse is to be inscribed. The upper underside 32 of the yoke 28 forms a channel-shaped and horizontally extending guideway 34. The yoke is provided with aligned bearings 36 below the guideway 34. The guidewa} and the aligned bearings 36 are arranged parallelly with a line intersecting the ends of pins 30.

A second frame 38 includes a central section 40 and two oppositely extending trunnions 42 which are journalled in the bearing 36 of the main frame. The frame 38 is held in adjusted position by two screws, one of which is shown at 44. The frame 38 also includes a centrally disposed, elongated and downwardly extending sleeve-type guide 46 which is formed integrally with the central section and trunnions.

A vertically extending shaft 50 is journalled for rotatable, movement in the frame. It extends through and below the sleeve-type guide 46 and through and above the central section 40. A knurled knob 52 for rotating the shaft is fixed to the upper end of the shaft by a set screw 54. The upper end of the knob is provided with a horizontally extending dovetailed slot 56 for slidably receiving an arm 58 which is shaped in cross section complementary to the dovetailed slot.

An elongated bearing 60, formed of Teflon is pivotally carried by a pin 61 which extends vertically from the upper side of arm 58. This bearing extends into and is guided by the guideway 34.

The lower end of shaft 50 has a collar 62 fixed thereto by a set screw 64. The lower portion of collar 62 is provided with a horizontally extending dovetail shaped slot 66 which slidably receives an arm 68 which is shaped in cross section to complement the shape of the slot 66.

An L-shaped bracket 70 is fixed to the underside of one end of the arm 68, the lower leg 72 of which is pro vided with a vertically extending hole 74, the wall of the hole forming a bearing for a vertically movable sleeve 76. The upper and lower ends of the sleeve are threaded. A knurled nut 77 is threaded onto the upper end of the sleeve and that nut is adapted to engage the upper side of leg 72 of bracket 70 to limit the extent of downward movement of the sleeve. The lower portion of the sleeve is split vertically as shown at 78 and the lower threads receive an externally knurled clutch type nut 80- which, when screwed to move upwardly, will cause slit-closing action to be imparted to the sleeve. The style 82 in the form of an inking pen or pencil extends through the sleeve 76 and is held in fixed position in the sleeve by the clutch nut 80.

The axis of the sleeve, and therefore the style 82, is parallel with the axis of shaft 50. A spring 84 is interposed between the top of clutch nut 80 and the underside of leg 72 of bracket 70. The force of the spring is such that the desired downward pressure is transferred from the lower end of the style 82 to the surface being inscribed.

Both arms 58 and 68 are held in horizontally adjusted position solely by friction. As shown in FIG. 3, a horizontally extending hole 85 receives a brake 86 such as Teflon. The brake is held in adjusted, pressure-exerting position by a screw 88. A like brake is provided for arm 68.

As seen in FIG. 3, a spring 90 is interposed between the top of the central section 40 of frame 38 and the underside of knob 52. The underside of the knob is recessed as at 92 for guiding the spring 90. The spring is under compression and normally resists downward movement of the knob whereby the bearing 60 is restrained from leaving the guideway 34, but it can be removed by forcing the knob downwardly.

In manipulating the instrument, the pins 30 on the legs 24 and 26 are aligned with the desired minor axis of the ellipse to be inscribed and the axis of the shaft 50 is positioned at the intersection of the minor and major axes of the ellipse to be inscribed. At this time, the frames 22 and 38 are perfectly erect. The arm 68 is then moved horizontally toward one of the pins 30 to a position in which the point of the style reaches a point for the desired width of the ellipse to be inscribed. Thereafter the shaft 50 is moved ninety degrees to the position shown in FIG. 2, and the upper arm 58 is moved horizontally to a position in which the point of the style reaches a point for the desired length of the ellipse to be inscribed.

When the shaft 50 is being turned by the knob 52, the frames 22 and 38 are gradually tilted from the position shown in FIG. 2 to an upright position, at which time the arms 58 and 68 intersect a line between the pins 30. Continuous turning will gradually effect tilting in the opposite direction, then reversal and finally the frames will be returned to the position shown in FIG. 2, completing an inscribed ellipse.

It is readily apparent from the foregoing that by the construction of the arm 68 relative to the shaft 50 and the arrangement of the spring-pressed style 82, the elaborate mechanism heretofore employed for manipulating the style to attempt to provide the proper pressure thereof on the surface being inscribed, has been eliminated. Further, by frictionally retaining the arms in adjusted position, the slot and retaining screw mechanism previously used for retaining the arms has been eliminated.

While ellipses could be drawn with the instrument shown in my previous Pat. No. 3,084,441, it was necessary, due to that construction, to provide the roller 92 and was somewhat tedious to operate. Moreover, in drawing an ellipse with that instrument, it was necessary to ink it in two stages. First approximately one-half of the ellipse was drawn. Then, since the roller had to cross the inked section, the further movement had to be delayed until the ink dried.

By use of the present invention inking of a complete ellipse can be done through one continuous motion.

Having described my invention, I claim:

1. An instrument for inscribing ellipses upon a surface, comprising in combination:

(A) a main frame having:

( 1) upright legs resting on said surface, (2) a yoke connecting the upper ends of the legs,

said yoke having:

(a) a longitudinally extending guideway arranged parallelly of said surface,

(3) bearing means on the frame having an axis disposed parallelly of the guideway and disposed intermediate the guideway and the foot ends of the legs;

(B) a second frame pivotally carried by the bearing means, said second frame forming a vertically extending guide;

(C) a vertically extending shaft journalled for vertical movement in said vertically extending guide;

(D) an arm above the bearing means;

(E) means on the upper portion of the shaft for supporting the arm for transverse movement relative to the axis of the shaft, said means including:

(1) a knob for turning the shaft, said knob being fastened to the shaft above the second mentioned frame;

(F) means on the arm guided by the guideway;

(G) a second arm;

(H) means at the lower portion of the shaft for directly carrying the second mentioned arm for transverse movement relative to the axis of the shaft;

(I) an inscriber;

(J) means on the second mentioned arm for directly supporting the inscriber on an axis parallel to the axis of the shaft;

(K) a spring on the second mentioned arm normally urging said inscriber downwardly;

(L) a spring under compression disposed between the ripper part of the second mentioned frame and the nob.

2. An instrument as defined in claim 1, characterized in that the first mentioned arm is slidably supported by the shaft, and further characterized to include:

(M) means for frictionally resisting free slidable movement of the first mentioned arm relative to the shaft.

3. An instrument as defined in claim 1, characterized in that the second mentioned arm is slidably supported by the shaft, and further characterized to include:

(M) means for frictionally resisting free slidable movenltlent of the second mentioned arm relative to the s aft.

4. An instrument as defined in claim 1, characterized in that the first mentioned arm is slidably supported by the shaft, and further characterized to include:

(M) means for frictionally resisting free slidable movement of the first mentioned arm relative to the shaft; and further characterized in that the second mentioned arm is slidably supported by the saft and further characterized to include:

(N) means for frictionally resisting free slidable movenlilent of the second mentioned arm relative to the s aft.

5. An instrument as defined in claim 1, characterized to include:

(M) an elongated bearing extending into the guide- (N) means on the first mentioned arm for pivotally carrying the elongated bearing.

6. An instrument as defined in claim 2, characterized to include:

(N) a spring normally urging the means (M) into engagement with the arm.

7. An instrument as defined in claim 3, characterized to include:

(N) a spring normally urging the means (M) into engagement with the arm.

8. An instrument as defined in claim 4, characterized to include:

(0) a spring connecting the second mentioned frame and shaft and normally urging the shaft, the arms and the inscriber upwardly with the means (F) in guided relationship with the guideway;

(P) an elongated bearing extending into the guidey; (Q) means on the first mentioned arm for pivotally carrying the elongated bearing. 623,

9. An instrument as defined in claim 8, characterized 1,174,365 to include: 5 2,067,387 (Q) a spring normally urging the means (M) into en- 2899748 gagement with the first mentioned arm; 3,084,441

(R) a spring normally urging the means (N) into engagement with the second mentioned arm.

Veronese et al. Bolt.

Gadd et a1. Bowen. Bowen.

l0 HARRY N. HAROIAN, Primary Examiner 

